This study develops multivariate models to predict swimming performance based on multidimensional assessment. 66 male (age 13.6 ± 0.6 y) and 67 female (11.5 ± 0.6 y) swimmers undertook a test battery including a sports background and training questionnaire, anthropometry, general and specific fitness tests, and technique. Competitive performance (LEN scores in three best events) was the predicted variable. A multiple linear regression model explained 82.4% of performance variability in males (based on age, sitting height, 30-min test, 6 × 50 m at 1:30, and swimming index) and 84.5% in females (age, 30-min test, 6 × 50 m at 1:30, and velocity at 50 m). Discriminant analysis using a four-group split-sample approach correctly classified 94.1% of the best male swimmers (based on age, 30-min test, 6 × 50 m at 1:30, shoulder extension, arm span, and height), and 71.0% of the best females swimmers (30-min test, horizontal floating, velocity at 50 m, and age). Chronological age was the main predictor of performance in this age category. Main predictive variables pertained to the anthropometric (particularly in males), specific fitness (aerobic speed and endurance), and technical domains (particularly in females). In these ages competitions should be organized according to year of birth and not by age categories.
José M. Saavedra, Yolanda Escalante and Ferran A. Rodríguez
Brittney Bernardoni, Tamara A. Scerpella, Paula F. Rosenbaum, Jill A. Kanaley, Lindsay N. Raab, Quefeng Li, Sijian Wang and Jodi N. Dowthwaite
We prospectively evaluated adolescent organized physical activity (PA) as a factor in adult female bone traits. Annual DXA scans accompanied semiannual records of anthropometry, maturity, and PA for 42 participants in this preliminary analysis (criteria: appropriately timed DXA scans at ~1 year premenarche [predictor] and ~5 years postmenarche [dependent variable]). Regression analysis evaluated total adolescent interscan PA and PA over 3 maturity subphases as predictors of young adult bone outcomes: 1) bone mineral content (BMC), geometry, and strength indices at nondominant distal radius and femoral neck; 2) subhead BMC; 3) lumbar spine BMC. Analyses accounted for baseline gynecological age (years pre- or postmenarche), baseline bone status, adult body size and interscan body size change. Gymnastics training was evaluated as a potentially independent predictor, but did not improve models for any outcomes (p < .07). Premenarcheal bone traits were strong predictors of most adult outcomes (semipartial r 2 = .21-0.59, p < .001). Adult 1/3 radius and subhead BMC were predicted by both total PA and PA 1-3 years postmenarche (p < .03). PA 3-5 years postmenarche predicted femoral narrow neck width, endosteal diameter, and buckling ratio (p < .05). Thus, participation in organized physical activity programs throughout middle and high school may reduce lifetime fracture risk in females.
Arja Sääkslahti, Pirkko Numminen, Harri Niinikoski, Leena Rask-Nissilä, Jorma Viikari, Juhani Tuominen and Ilkaa Välimäki
The purpose of this study was to examine patterns of physical activity (PA) during a single weekend to ascertain possible relationships between PA and anthropometry, fundamental motor skills, and CHD risk factors among 105 normal male and female children, aged 3–4 years. The children played, when awake, on the average for 14 hr, 16 min indoors and for 5 hr, 12 min outdoors of which low activity playing accounted about 4 hr. Notable gender differences were observed in the intensity of PA but not in fundamental motor skills and CHD risk factors. The results suggest that physical activity is weakly related to fundamental motor skills and CHD risk factors at an early age. The association between PA and body size was modified by gender (p = .024): The girls who played indoors a lot were heavier than the others, and the boys who played much more outdoors were heavier in relation to other boys. The associations between PA and motor skills as well as PA and CHD risk factors were also highly gender-dependent: The boys benefited from interacting with parents, while the girls benefited from independence. The most influential factors seemed to be the amount of playing outdoors, the amount of high level play activities, as well as interaction with parents.
Maroje Soric, Marjeta Misigoj-Durakovic and Zeljko Pedisic
The purpose of this study was to assess dietary intake and body composition of prepubescent girls competing in 3 aesthetic sports (artistic and rhythmic gymnastics and ballet). Because physiological demands of ballet training are similar to those in other aesthetic sports, ballet dancers were, for the purpose of this study, regarded as athletes. The sample consisted of 39 athletes (median age, 11 years, range 9–13) and 15 controls (median age, 11 years, range 10–12). Dietary intake was assessed using a quantitative food frequency questionnaire, and body composition, by means of anthropometry. There was no significant difference in total energy intake between groups, but there was a significant difference in energy substrate distribution. Artistic gymnasts reported significantly higher carbohydrate and lower fat contribution to total energy (57% ± 6% and 29% ± 5%, respectively) than rhythmic gymnasts (48% ± 6% and 36% ± 5%), ballet dancers (51% ± 4% and 34% ± 3%), or controls (51% ± 5% and 34% ± 4%). Relative to body weight, artistic gymnasts reported higher intake of carbohydrates (9.1 ± 4.2 g/kg) than rhythmic gymnasts (5.6 ± 3.1 g/kg), ballet dancers (6.6 ± 2.5 g/kg), or controls (5.4 ± 1.9 g/kg). Artistic gymnasts also had the lowest body-fat percentage among the groups. In all the groups mean reported daily intakes of most nutrients were higher than the current daily recommended intakes. The exceptions were dietary fiber and calcium. The proportion of athletes with an inadequate reported intake was highest for phosphorus (33%), followed by vitamin A and niacin (18%) and zinc (13%).
Tyler L. Goodale, Tim J. Gabbett, Trent Stellingwerff, Ming-Chang Tsai and Jeremy M. Sheppard
To investigate the physical qualities that differentiate playing minutes in international-level women’s rugby sevens players.
Twenty-four national-level female rugby sevens players underwent measurements of anthropometry, acceleration, speed, lower- and upper-body strength, lower-body power, and aerobic fitness. Playing minutes in international competition were used to differentiate players into 2 groups, a high- or low-playing-minutes group. Playing minutes were related to team selection, which was determined by the coaching staff. Playing minutes were therefore used to differentiate performance levels.
Players in the high-playing-minutes group (≥70 min) were older (mean ± SD 24.3 ± 3.1 vs 21.2 ± 4.3 y, P = .05, effect size [ES] = 0.77 ± 0.66, 90% confidence limit) and had greater experience in a national-training-center environment (2.4 ± 0.8 vs 1.7 ± 0.9 y, P = .03, ES = 0.83 ± 0.65), faster 1600-m time (374.5 ± 20.4 vs 393.5 ± 29.8 s, P = .09, ES = –0.70 ± 0.68), and greater 1-repetition-maximum upper-body strength (bench press 68.4 ± 6.3 vs 62.2 ± 8.1 kg, P = .07, ES = 0.80 ± 0.70, and neutral-grip pull-up 84.0 ± 8.2 vs 79.1 ± 5.4 kg, P = .12, ES = 0.68 ± 0.72) than athletes who played fewer minutes. Age (rs = .59 ± ~.28), training experience (rs = .57 ± ~.29), bench press (r = .44 ± ~.36), and 1600-m time (r = –.43 ± ~.34) were significantly associated with playing minutes. Neutral-grip pull-up and bench press contributed significantly to a discriminant analysis. The average squared canonical correlation was .46. The discriminant analysis predicted 7 of 9 and 6 of 10 high- and low-playing-minutes athletes, respectively.
Age, training experience, upper-body strength, and aerobic fitness differentiated athlete playing minutes in international women’s rugby sevens.
Jeremy M. Sheppard, Sophia Nimphius, Greg G. Haff, Tai T. Tran, Tania Spiteri, Hedda Brooks, Gary Slater and Robert U. Newton
Appropriate and valid testing protocols for evaluating the physical performances of surfing athletes are not well refined. The purpose of this project was to develop, refine, and evaluate a testing protocol for use with elite surfers, including measures of anthropometry, strength and power, and endurance.
After pilot testing and consultation with athletes, coaches, and sport scientists, a specific suite of tests was developed. Forty-four competitive junior surfers (16.2 ± 1.3 y, 166.3 ± 7.3 cm, 57.9 ± 8.5 kg) participated in this study involving a within-day repeated-measures analysis, using an elite junior group of 22 international competitors (EJG), to establish reliability of the measures. To reflect validity of the testing measures, a comparison of performance results was then undertaken between the EJG and an age-matched competitive junior group of 22 nationally competitive surfers (CJG).
Percent typical error of measurement (%TEM) for primary variables gained from the assessments ranged from 1.1% to 3.0%, with intraclass correlation coefficients ranging from .96 to .99. One-way analysis of variance revealed that the EJG had lower skinfolds (P = .005, d = 0.9) than the CJG, despite no difference in stature (P = .102) or body mass (P = .827). The EJG were faster in 15-m sprint-paddle velocity (P < .001, d = 1.3) and had higher lower-body isometric peak force (P = .04, d = 0.7) and superior endurance-paddling velocity (P = .008, d = 0.9).
The relatively low %TEM of these tests in this population allows for high sensitivity to detect change. The results of this study suggest that competitively superior junior surfers are leaner and possess superior strength, paddling power, and paddling endurance.
Shane Ball, Mark Halaki, Tristan Sharp and Rhonda Orr
Context: Rugby union is a physically demanding collision sport with high injury rates. There is a common perception that higher training loads result in greater injury risk in field-based sports. Objectives: To determine injury, anthropometric, and physical-performance characteristics in junior rugby union players and investigate the interaction between training load and injury across a competitive season. Design: Prospective cohort study. Methods: Fifty-one players (age 19.2 ± 0.7 y) from an under-20 university rugby union team (forwards, n = 27; backs, n = 24) participated in a study conducted over a competition season. Training load, injury characteristics, anthropometry, physiological performance, and match time-loss injury incidence were observed. Results: Backs had significantly lower body mass (ES [95% CI] = 1.6 [0.9, 2.2]), skinfold thickness (ES = 1.1 [0.5, 1.7]), strength (squat ES = 0.6 [0.0, 1.2], deadlift ES = 0.6 [0.0, 1.1], bench press ES = 0.9 [0.4, 1.5]), lower-body power (ES = 0.4 [−0.2, 1.0]), and higher maximal aerobic capacity (ES = −0.3 [−0.8, 0.3]) than forwards. Match injury incidence was 107.3 injuries/1000 player hours (forwards 91.4/1000, backs 125.5/1000) during preseason and 110.7 injuries/1000 player hours (forwards 124.1/1000, backs 95.2/1000) during in-season. Forwards showed higher incidence of joint and ligament (P = .049) and upper-limb (P = .011) injuries than backs. No significant relationship between overall training load and match injury incidence was found. However, lower match injury incidence was associated with higher weekly training volume in backs (P = .007). Conclusions: Positional differences in body composition, performance, injury characteristics, and match injury patterns were identified in junior university rugby union players, indicating the need for position-specific training programs to reduce risk of injury.
Louise M. Burke, Asker E. Jeukendrup, Andrew M. Jones and Martin Mooses
Distance events in Athletics include cross country, 10,000-m track race, half-marathon and marathon road races, and 20- and 50-km race walking events over different terrain and environmental conditions. Race times for elite performers span ∼26 min to >4 hr, with key factors for success being a high aerobic power, the ability to exercise at a large fraction of this power, and high running/walking economy. Nutrition-related contributors include body mass and anthropometry, capacity to use fuels, particularly carbohydrate (CHO) to produce adenosine triphosphate economically over the duration of the event, and maintenance of reasonable hydration status in the face of sweat losses induced by exercise intensity and the environment. Race nutrition strategies include CHO-rich eating in the hours per days prior to the event to store glycogen in amounts sufficient for event fuel needs, and in some cases, in-race consumption of CHO and fluid to offset event losses. Beneficial CHO intakes range from small amounts, including mouth rinsing, in the case of shorter events to high rates of intake (75–90 g/hr) in the longest races. A personalized and practiced race nutrition plan should balance the benefits of fluid and CHO consumed within practical opportunities, against the time, cost, and risk of gut discomfort. In hot environments, prerace hyperhydration or cooling strategies may provide a small but useful offset to the accrued thermal challenge and fluid deficit. Sports foods (drinks, gels, etc.) may assist in meeting training/race nutrition plans, with caffeine, and, perhaps nitrate being used as evidence-based performance supplements.
Brendan H. Lazarus, William G. Hopkins, Andrew M. Stewart and Robert J. Aughey
only advance with age. 6 While the effect of age on performance has implications for player-list management and team selection, the effect of age on match outcome in elite Australian football is unknown. Research on the effects of anthropometry in Australian football has mainly focused on describing
Anthony N. Turner, Geoff Marshall, Angelo Noto, Shyam Chavda, Nathan Atlay and David Kirby
-scaled affordances, suggests that an individual self optimizes for a particular task based on their anthropometry (eg, leg length [body-scaled]) or on capabilities such as strength (action-scaled). For example, when a ball is thrown overhead, the affordance concept aims to explain how an athlete knows not only when